SR API Quick Reference
This page contains a quick guide to the
For more information, make sure you check the rest of the documentation.
Import the API
In order to use the
sr.robot3 API you first need to import it into your code:
from sr.robot3 import *
Initialising your robot
robot = Robot()
Initialisation without waiting for the start button
robot = Robot(wait_for_start=False) # Code here runs before the start button is pressed robot.wait_start() # wait for the start button
Initialisation with extra logging
You can also tell the robot to print extra logging information, although this will create a lot of logs.
robot = Robot(debug=True)
Selecting which board to control
If you only have one board of a given type plugged into your robot, then you can use its singular name:
robot.power_board robot.motor_board robot.servo_board robot.arduino
If you have multiple boards of a given type plugged into your robot, you must index them by serial number:
The outputs on the power board will turn on when you initialise your robot and turn off when your code ends.
Turn on and off the power outputs
# Turn all of the outputs on robot.power_board.outputs.power_on() # Turn all of the outputs off robot.power_board.outputs.power_off() # Turn a single output on robot.power_board.outputs[OUT_H0].is_enabled = True # Turn a single output off robot.power_board.outputs[OUT_H0].is_enabled = False
Reading voltage and current
# Read the current of an individual output current = robot.power_board.outputs[OUT_H0].current # Read the current and voltage from the LiPo battery voltage = robot.power_board.battery_sensor.voltage current = robot.power_board.battery_sensor.current
The power board has an on-board piezoelectric buzzer.
# Play a standard note C6 -> C8 included for 0.5s robot.power_board.piezo.buzz(Note.C6, 0.5) # Play a tone at 1047Hz for 1 second robot.power_board.piezo.buzz(1047, 1) # Play a tone at 500Hz tone for 2 seconds and wait for it to finish robot.power_board.piezo.buzz(500, 2, blocking=True)
You can set the power of each motor on the board between -1 and 1.
If you change the power of your motor too rapidly, the overcurrent protection may be triggered.
robot.motor_board.motors.power = 1 robot.motor_board.motors.power = -1
Special motor values
Setting a motor to
BRAKE is equivalent to power level
# This is the same operation robot.motor_board.motors.power = BRAKE robot.motor_board.motors.power = 0
COAST will stop applying power to the motors. This will mean they continue moving under the momentum they had before and slowly come to a stop.
robot.motor_board.motors.power = COAST
You can set the position of each servo output on the board between -1 and 1.
robot.servo_board.servos.position = -1 robot.servo_board.servos.position = 1
You can also set the position to
0, which is the approximate centre.
Taking a photo
It can sometimes be useful to save a photo of what markers the robot can see:
robot.camera.save("my-photo.jpg") # Save my-photo.jpg to the USB drive
Capturing an openCV array
Take a photo using the webcam, and return the image data as an OpenCV array:
frame = robot.camera.capture()
Looking for markers
You can take a photo with the camera and search for markers:
markers = robot.camera.see()
There are various bits of information available about visible markers:
for marker in markers: marker.id # The ID of the marker marker.size # Physical size of the marker in mm. # Position of the marker on the image (physical kits only) marker.pixel_centre # The co-ordinates of the centre of the marker marker.pixel_corners # A list of corners of the marker # Position of the marker marker.position.distance # Distance away from the camera in mm marker.position.horizontal_angle # angle to the marker in radians marker.position.vertical_angle # angle to the marker in radians # Orientation of the marker marker.orientation.yaw marker.orientation.pitch marker.orientation.roll
Setting the mode of a pin
robot.arduino.pins.mode = OUTPUT robot.arduino.pins.mode = INPUT robot.arduino.pins.mode = INPUT_PULLUP
You can set the output for a pin of the Arduino:
robot.arduino.pins.mode = OUTPUT robot.arduino.pins.digital_write(True) robot.arduino.pins.digital_write(False)
You can read a digital value from the pins of the Arduino:
robot.arduino.pins.mode = INPUT robot.arduino.pins.mode = INPUT_PULLUP value = robot.arduino.pins.digital_read() value = robot.arduino.pins.digital_read()
You can read an analogue value from the analogue pins of the Arduino:
robot.arduino.pins[A0].mode = INPUT value = robot.arduino.pins[A0].analog_read()
The API also makes some information about where your code is running
Starting zone for a match
zone = robot.zone # -> 0, 1, 2, or 3
This is set to
COMP when your robot is in a match.
robot_mode = robot.mode # -> DEV or COMP
USB stick path
This is the path to where your USB stick is mounted.
You can use this to save files and information to the drive.
usb_key_path = robot.usbkey
A boolean value indicating whether or not the code is running in the simulator. This value is True when in the simulator and False when on the robot.
value = robot.is_simulated